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Posts Tagged ‘earth block’

$300 Geopolymer CEB House (click to enlarge)

$300 Geopolymer CEB House (click to enlarge)


I’ve added a third entry in ‘The $300 House Open Design Challenge’. CEBs are popular and practical, and some of you may be thinking of using them for columns, next to wood stoves, interior walls or as a design element. They would make a great center column in a roundhouse. Geopolymer CEBs turn to actual stone as explained in several previous posts.

Please vote on my projects. It’s shocking how few people have voted. This means a handful of votes changes the ranking considerably. Here’s the direct link to the $300 Geopolymer CEB House.

Update: Come on guys, help me out! Hundreds of thousands of people have read this blog and only 18 people have rated this CEB house. That’s a bit discouraging when you consider how much work goes into this blog (almost 600 posts, over 2,000 comments). I’m glad to see my Stone Dome in the top 10. I know this CEB house and my $300 earthbag house are also extremely practical, but I need your support.

Update: Yeah to go team. The Stone Dome is currently #3, the CEB house pictured above is #7, and the $300 Earthbag House is #18. They all jumped in ranking from just a few votes. Thank you! Also note how earthbag houses are now ranked #1, 2 and 3!

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Full text of the video is available on my Naturalhouse’s YouTube channel. This blog post will focus on summarizing the test results. Please note that even though half the samples were earthen blocks, you can do these same tests on earthbags to help develop a good soil mix. A link to additional tests can be found at end of this blog post. Also note, although I say “clay” for brevity it’s actually clay soil not pure clay that’s used in all these tests.

Earth Block and Earthbag Testing Results (click to enlarge)

Earth Block and Earthbag Testing Results (click to enlarge)


The strongest sample turned out to be the earthbag made with vetiver, clay soil and rice hulls. This sample not only passed every test, including zero damage in the drop test, it also had a distinctly different feel than the others. It made a ringing sound when it was dropped that reminded me of clay brick. The sample was lighter weight due to the hulls, and, of course, would have improved insulation value. It probably gained strength from compaction and the long vetiver fibers.

Adding rice hulls to adobe and other forms of earthen construction is an ancient process that begs further research. For instance, I just learned rice hull/clay was the traditional method for building houses in Taiwan, and now the high cost of energy for air conditioning in Taiwan is creating renewed interest in this ancient technique. (No air conditioning needed in a properly designed adobe or earthbag house.) Note the similarity with straw/clay that has proven a huge success in Europe for centuries.

For additional soil tests, please refer to Patti Stouter’s excellent soil testing guide Soil Tests for Earthbag.

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Star Top Compressed Earth Block Presses

Star Top Compressed Earth Block Presses


Compressed earth blocks (CEBs) have countless uses and come in dozens of shapes (many more than shown here). They are commonly used for residential and commercial structures, earthquake resistant structures, privacy walls, columns, bond beams, pavers, planters, stairs, etc. For instance, you could make CEB columns on your house and privacy walls and stack earthbags between. (See Confined Earthbag.) Right now I’m making an outdoor oven with CEBs. The possibilities are endless.

Star Top Construction and Blockprasan Co., Ltd. manufactures very high quality compressed earth block presses in Nakhon Pathom, Thailand. When you look at the ¾” (2 cm) thick steel parts, it sure looks like these machines would last well over 100 years with continual use. Note: I am not paid in any way for promoting these presses. I’m very impressed with their ruggedness and quality and would like people to know about their products. In fact, I’ve admired them for about 4-5 years and have finally got around to telling people about them.

Many people know about the Aureka presses made in India. Here’s a brief comparison:
Star Top Standard press makes 10 types of blocks and costs $800 US.
Star Top Hitop press makes 30 types of blocks and costs $900 US.
Aureka 3000 multi-mould manual earth block press as shown here costs $X [cost not available yet, but it’s roughly twice the cost if I remember correctly]

Star Top also manufactures a whole line of block making equipment, including hammermills to pulverize soil, mortar mixers to mix the soil with cement, and machine and hand-operated block presses. I’m guessing there are several thousand small shops in Thailand with a similar set of machines. They quoted us $4,171 for the whole set of machines to make blocks by hand and $8,843 for the machine operated set that makes two blocks at a time.

Sample CEB Block Shapes (many more available)

Sample CEB Block Shapes (many more available)

Note the holes in the CEBs. Rebar is inserted through the blocks and then the holes are filled with cement grout. There is no mortar between this type of CEB.

Star Top website
Star Top Technology
Phone in Thailand: 034-2679534
Email: startop@blockprasan.com
Cost of CEBs at Phu Phan Research Center: 23 cents
Standard size of CEBs: 12.5x25x10 cm high (you can make other sizes)

Update: This video shows how the press works. It’s actually a competing brand made by K. Thai Machinery Company that looks and operates virtually the same way.

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Cheap and easy compressed earth block (CEB) floors

Cheap and easy compressed earth block (CEB) floors


Here’s a great, low cost way to build floors with compressed earth blocks. This Instructable is by Velacreations. Visit their website for more great ideas.

When considering what material to use for a floor, few people look beyond a concrete slab, with something like tile or carpet as a finish. For us, however, there were several factors that made a stabilized compressed earth brick (SCEB) [or just CEB for short] floor far more appealing, including cost, skill, and time required.

Read the rest of the article for free at Cheap and Easy Brick Floors Instructable

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If you’ve been watching our videos, you’ve seen us making various earthen blocks. This one here is the best one so far. It has clay and rice hulls. Another very good block was the clay with vetiver grass. So I had the idea to combine the best – the rice hulls and the vetiver. That’s what we’re testing today. This block back here is adobe, just the traditional adobe mix. We’re using this wood form that’s 10”x14”x6” high. That’s a typical size earthen block. You could put these same materials in earthbags, but it’s a lot of extra work. It would only be worthwhile probably if you wanted something special like a lightweight insulated earthbag.

We’re using the same basic ingredients – rice hulls, chopped vetiver for fiber to hold the block together, sifted sand and clay soil. This is not pure clay, this is clay soil. You have to experiment with your own soil and ingredients to get the right mix, but this is what we’ve been using approximately 2:1 — two parts clay soil to one part sand, one part rice hulls, one part vetiver, and enough water to make a stiff mix, but no extra water. Add the clay first – the clay soil actually – with a little bit of water and let it soak. This saves a lot of mixing. Add a little at a time. And again, it would be easier to make this in large quantities in a pit or on a large tarp. We’re just making one small sample here. Add the ingredients in layers to reduce mixing. Add the fiber at the end to make mixing easier.

I like the vetiver grass, because it adds termite resistance and tensile strength. We made a second small batch in order to fill this mold. I think this is going to be our best block so far. We’re combining everything we’ve learned to make a block that’s stronger, lighter, insulating and insect resistant. Another thing we’re doing this time is we’re pouring it in the mold in place. This adobe block we made elsewhere and it cracked as I was carrying it over here to dry. This time we’ll make it right here and we won’t move it around. We should have a stronger block. In about two weeks or so we’re going to test all these blocks that we’ve made and see which ones are the strongest and the best. So stay tuned for our next video.

Naturalhouse’s YouTube channel now with 84 natural building videos.

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Today we’re experimenting with rice hull ash and road base. We’re using a small measuring device so we can get about 10% rice hull ash. This is what rice hull ash looks like. It’s hulls from rice that’s been burned. It looks like ash from a forest fire. It’s a natural pozzolan which can make the soil harder. We’re going to start off with about 10%. I’m adding it in thin layers and tamping it. This will simulate an earthbag. Okay, it’s pretty solid, just like you would tamp an earthbag. The idea is to use rice hull ash in replacement of cement. That big bag over there was only $3.60 and, of course, cement is much more expensive. Now we’re making a second test block with no burned rice hulls, no ash, just the road base so we can compare the two blocks. We’re just adding a little earth at a time, the same consistency, the same amount of moisture we put in earthbags. Just spread it out in thin layers. You notice the plastic on the tamper so it doesn’t stick. So here’s our finished rammed earth block with no ash. We’ll see how they compare after they dry. This one had a little more moisture and seems like it’s stronger, but then again this one has ash, which should add some strength, so we’ll see. I noticed this was crumbly when I took it out of the form, which means it probably had a lack of moisture. Some people may think this is just earth, it can’t be strong. But this is rammed earth, which can last thousands of years. You can learn more on our earthbag website. But just this here alone can last thousands of years. It gains its strength from clay. The clay is like a flat platelet, kind of like the shape of my hand. You put the platelets together and under pressure they create a molecular bond that’s very, very strong. Very compact, very dense. So this can last for a very long time. We’ll wait a little while and take it out of the form. Make sure you use very strong forms. And also note, you don’t have to tamp it and you don’t have to make it in blocks. This is just a test. You could build a whole wall in the same way, not individual blocks. So there are many things you can do with this technology. And this plastic – we tested this out – and it works really well. Here are the final blocks. You can see that this one had more moisture. You can see the smooth, solid clay on the top and even on the sides. You can see more pore space here, more small holes between the particles, so I’m guessing that this is going to be stronger even though we put the ash in this one over here to make it stronger. So we’ll see in maybe a week or two. If you do this, I highly recommend metal forms. The wood form is just too fragile, too easy to break. And with a metal form, you could tamp it much harder and get very, very strong blocks.

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